TUESDAY, Dec. 8, 2015 (HealthDay News) — Having an optimistic attitude after a heart attack may be good for your health, Harvard researchers report.

Two weeks after a heart attack, patients who had a positive attitude were less likely to be readmitted to the hospital. After six months, these patients were more physically active than less optimistic patients, the study found.

"In contrast, gratitude, assessed right after the heart attack, actually had no effect on readmissions or increasing physical activity," said lead researcher Dr. Jeff Huffman, an assistant professor of psychiatry at Harvard, in Boston.

For the study, Huffman and colleagues studied 164 patients. The researchers assessed a patient's optimism and gratitude two weeks after the heart attack and again six months later.

These findings suggest that all positive emotional experiences may not be alike when it comes to their potential effects on heart health, he said.

"It may be that optimism, as a forward-looking expectation, may help people to feel that they can make healthy changes and thrive," Huffman said.

Gratitude, however, often focuses on immediate or past events, and while it may have benefits, these may be less connected to taking active steps in managing one's health, he said.

This connection between optimism and positive health outcomes was independent of patients' age, sex, health or level of activity before the heart attack, Huffman said.

Huffman said these findings may make it worthwhile to find ways to make patients more optimistic after a heart attack as a way of improving their recovery.

"Finding ways to cultivate optimism after a major health event may lead to substantially better recovery, though there have not yet been rigorous studies to test whether it is possible to make less optimistic people more hopeful and whether that improves health," he said. This particular study was not designed to prove a cause-and-effect relationship between optimism and recovery from a heart attack.

The report was published online Dec. 8 in the journal Circulation.

Another study, published last spring in the journal Psychosomatic Medicine, found that among nearly 400 heart attack patients the most pessimistic patients were twice as likely to suffer from serious complications such as a second heart attack, heart surgery or death in the four years following their initial heart attack, compared with the most optimistic patients.

Dr. Gregg Fonarow, a professor of cardiology at the University of California, Los Angeles, said, "There has been great interest as to whether psychological factors, including having a positive outlook and feeling gratitude, can impact cardiovascular outcomes."

However, this latest study is too small to provide enough information to really tell if trying to get patients to be more optimistic can improve outcomes, he said.

"Further analyses will be necessary to replicate these findings, as well as determine whether interventions that focus on patients' level of optimism can have a favorable impact on cardiovascular outcomes," Fonarow said.